Theropod Tracks Research Articles

Reanalysis of Wupus agilis (Early Cretaceous) of Chongqing, China as a Large Avian Trace: Differentiating between Large Bird and Small Non-Avian Theropod Tracks.

Trace fossils provide the only records of Early Cretaceous birds from many parts of the world. The identification of traces from large avian track-makers is made difficult given their overall similarity in size and tridactyly in comparison with traces of small non-avian theropods. Reanalysis of Wupus agilis from the Early Cretaceous (Aptian-Albian) Jiaguan Formation, one of a small but growing number of known avian-pterosaur track assemblages, of southeast China determines that these are the traces of a large avian track-maker, analogous to extant herons. Wupus, originally identified as the trace of a small non-avian theropod track-maker, is therefore similar in both footprint and trackway characteristics to the Early Cretaceous (Albian) large avian trace Limiavipes curriei from western Canada, and Wupus is reassigned to the ichnofamily Limiavipedidae. The reanalysis of Wupus reveals that it and Limiavipes are distinct from similar traces of small to medium-sized non-avian theropods (Irenichnites, Columbosauripus, Magnoavipes) based on their relatively large footprint length to pace length ratio and higher mean footprint splay, and that Wupus shares enough characters with Limiavipes to be reassigned to the ichnofamily Limiavipedidae. The ability to discern traces of large avians from those of small non-avian theropods provides more data on the diversity of Early Cretaceous birds. This analysis reveals that, despite the current lack of body fossils, large wading birds were globally distributed in both Laurasia and Gondwana during the Early Cretaceous.

First Record of Theropod and Ornithopod Tracks and Detailed Description of Sauropod Trackways from the Tacuarembó Formation (Late Jurassic-?Early Cretaceous) of Uruguay

The record of dinosaur tracks and trackways from the Tacuarembó Formation (Late Jurassic-?Early Cretaceous) is described in detail: two trackways and four isolated tracks. Ichnites are preserved in sandstones of interdune facies of the Batoví (lower) Member. The interpretation herein presented indicates a sauropod affinity of the trackways, while the isolated prints are considered to have been made by an ornithopod and small theropods. The fossil record for this formation was primarily integrated by fresh-water organisms. The presence of new groups (sauropods and ornithopods) has specially contributed to the reconstruction of the terrestrial fauna, represented up until this time only by theropods.

Flattened fossil footprints: Implications for paleobiology

Abstract Studies of natural casts of dinosaur footprints associated with very thin mudstone and siltstone intervals in thick sand-dominated sequences often reveal casts that are significantly flattened due to the differential effects of overburden pressures on different lithologies. They are in effect squeezed, vise-like, between two thick, non-compactable sand layers. Thus, the sand filled tracks (casts) are flattened or widened as the ductile layers are compressed. Such flattening, here described from five localities, is a previously unreported phenomenon with implications for vertebrate ichnology. Present evidence suggest that significant flattening is not evident in most sequences in which mudstone and siltstone intervals are thicker, even though overburden pressures may have been comparable. Examples from the Jurassic of North America and the Cretaceous of China show that the flattening (widening) of tridactyl theropod tracks leads to predictable changes in track cast morphology, which may influence interpretations of track maker identity, and ichnotaxonomy. In the theropod dominated samples described here, such extramorphological changes differentially affect the shape of the whole cast and individual digit trace casts making them appear more “fleshy” and sometimes deceptively convergent with ornithopod tracks.

Tracking the yellow dragons: Implications of China's largest dinosaur tracksite (Cretaceous of the Zhucheng area, Shandong Province, China)

Surfaces with more than 2200 dinosaur footprints from the Huanglonggou (Yellow Dragon Valley) site near Zhucheng, in Shandong Province, were excavated for scientific study and with a view to future development as an educational site suitable for further research and tourism. Although geographically close to spectacular and historically famous Upper Cretaceous sites yielding vast bone assemblages, representing giant hadrosaurs and other dinosaurs from the Wangshi Group, the tracksite is in the Lower Cretaceous Yangjiazhuang Formation (equivalent in part to the Longwangzhuang Formation), represents an entirely different dinosaurian fauna, dominated by small theropods. In contrast to a recent pre-excavation study of a localized outcrop which identified only three theropod track morphotypes, in a sample of 135 tracks, the present study has identified at least 2000 additional tracks including those of sauropods and turtles. It is therefore possible to present a more complete interpretation of the site based on the larger and more diverse track assemblage presently exposed. Three theropod track morphotypes are identified as grallatorid morphotypes A and B, with the latter assigned to Grallator yangi comb. nov., and Corpulentapus lilasia . Tracks have been identified from at least 5 levels, of which level 4 exhibits the vast majority in an excellent state of preservation. Other recent studies, which we re-evaluate, suggest the tracks help define an ENE–WSW shoreline with the lake center to the SSE. In terms of number of tracks documented the Huanglonggou site is one of the largest dinosaur tracksites in China, or indeed in the world. • The largest mapped dinosaur tracksite in China • Five trackway morphotypes, most with exquisite preservation • Shore line micro-paleogeography mapped in fine detail • Unique track superimposition patterns are identified and explained.

Theropod and Ornithischian Footprints from the Middle Jurassic Yanan Formation of Zizhou County, Shaanxi, China

New tracksites reported from the Zizhou area elucidate the nature of the Early-Middle Jurassic dinosaurian ichnofaunas in Shaanxi Province. The assemblage is composed of footprints and trackways of medium- to large-sized theropods that show similarities with both the ichnogenera Kayentapus and Eubrontes and of small bipedal ornithischians that are referred to AS Anomoepus isp. Additionally tracks of a quadruped are present and assigned to Deltapodus isp. that may be related to a stegosaurian. Anomoepus isp. is similar to the holotype of Shensipus tungchuanensis which is, although apparently lost, re-assigned here and considered to be a subjective junior synonym of Anomoepus. It is therefore placed in new combination as Anomoepus tungchuanensis comb. nov. Identical tracks have been reported from well-preserved trackways both in the Zizhou and Shenmu areas, where they also co-occur with theropod tracks (Kayentapus and Grallator) and tracks of quadrupedal ornithischians (Shenmuichnus and Deltapodus). Thus, it appears that the carbonaceous (coal-bearing) facies of the region reveal ichnofaunas with both relatively abundant saurischian (theropod) and ornithischian tracks. This is in contrast with many areas where the ichnofaunas are heavily or exclusively saurischian (theropod) dominated.

First report on dinosaur tracks from the Burro Canyon Formation, San Juan County, Utah, USA – evidence of a diverse, hitherto unknown Lower Cretaceous dinosaur fauna

The newly discovered White Mesa tracksite in the Burro Canyon Formation represents a snapshot of a diverse, Lower Cretaceous dinosaur fauna from south-eastern Utah. The tracks were found at a construction site where the sandstone had been bulldozed and broken up. All tracks were found as deep, well-preserved natural casts on the underside of the sandstone slabs. Individual theropod tracks are 19–57 cm in length; one peculiar track shows evidence of a possible pathological swelling in the middle of digit III and an apparently didactyl track is tentatively assigned to a dromaeosaurid. Individual sauropod tracks are found with pes lengths of 36–72 cm, and interestingly, three distinct shapes of manus tracks, ranging from wide banana shaped to rounded and hoof-like. Ornithopods are represented with individual tracks 18–37 cm in length; a single track can possibly be attributed to the thyreophoran ichnogenus Deltapodus . Zircon U-Pb dating places the track-bearing layer in the Barremian, contemporary to the lower Yellow Cat Member of the Cedar Mountain Formation, which has a similar faunal composition based on both tracks and body fossils. This new track-fauna demonstrates the existence of a diverse dinosaurian assemblage in the lower part of the Burro Canyon Formation, which hitherto is not known to yield skeletalre mains.

Elongated theropod tracks from the Cretaceous Apenninic Carbonate Platform of southern Latium (central Italy

Elongated theropod tracks from the Cretaceous Apenninic Carbonate Platform of southern Latium (central Italy

First report of bird tracks (Aquatilavipes) from the Cedar Mountain Formation (Lower Cretaceous), eastern Utah

More than 130 footprints representing ~43 trackways of birds (avian theropods) and two non-avian theropods occur as seven separate assemblages on loose blocks recovered from the Poison Strip Member of the Cedar Mountain Formation, near the Stikes Quarry locality in eastern Utah. Six of assemblages, four with bird tracks and two with small non avian theropod tracks, are inferred to originate from the same stratigraphic horizon, and can therefore be considered part of the same ichnofauna. The seventh assemblage comes from a different horizon a few meters above that yielding the other six assemblages. The bird tracks are all attributed to the ichnogenus Aquatilavipes, a track type morphologically similar to those of modern shorebirds. The ichnogenus is also known from broadly coeval ichnofaunas from South Dakota and Canada, and the identification is confirmed by detailed comparative analysis of available Aquatilavipes samples using bivariate and multivariate analyses. This is the first definitive report of bird tracks from the Cedar Mountain Formation and the first evidence of birds from this otherwise richly fossiliferous unit. The ichnofauna is therefore quite unique in comparison with others from this same formation.

Geometric morphometric analysis applied to theropod tracks from the Lower Cretaceous (Berriasian) of Spain

AbstractGeometric morphometric methods applied to theropod tracks from the Huérteles Formation (Berriasian, Spain) are here shown to be invaluable for drawing comparisons between theropod tracks with different preservation modes (true tracks, shallow undertracks and natural casts) or differing in the preservation of anatomical features (e.g. digital pads). Principal components analysis and thin‐plate spline methods can quantitatively distinguish between the broad groups of tracks in a sample and establish the main differences between them. These methods offer a promising approach for estimating ichnodiversity, achieved by evaluating just the morphology of the tracks independent of other factors such as size. The theropod tracks of the Huérteles Formation can be classified into two broad groups: minute‐to‐medium‐sized gracile theropod tracks (Kalohipus bretunensis) and medium‐to‐large‐sized robust theropod tracks (Iberosauripus). The presence of a third group of more gracile medium‐to‐large‐sized theropod tracks (Megalosauripus) cannot be proven with certainty on the basis of the current data. These results indicate that the theropod ichnodiversity of the Huérteles Formation is probably lower than that estimated by means of conventional methods alone (e.g. qualitative description of the tracks) and that many of the described theropod morphotypes may represent extramorphological or ontogenetic variations of other morphotypes.

Re-description of the partially collapsed Early Cretaceous Zhaojue dinosaur tracksite (Sichuan Province, China) by using previously registered video coverage

A re-description of the Early Cretaceous Zhaojue dinosaur tracksite (Sichuan Province, China) is the major focus of the present work. The tracksite is located in an active copper mine, and a dinosaur track-bearing surface of about 1500 m2 (named tracksite I) initially discovered in 1991, has since almost completely collapsed due to ongoing quarry activities. Only about 5% of the initial surface still remains in place (named “remaining tracksite”), while due to the collapse a few new but rather poorly-preserved tracks were unearthed on an underlying level. While the tracks still in place were studied using common field techniques, a schematic tracksite map of the collapsed surface was drawn based on a “corrected orthophotograph” that was generated from overview photographs and from video frames. Fortunately, the resolution of some of the close-up video frames is sufficiently high to observe general track morphology, and to re-interpret previously wrongly identified trackways. Here, we report a quite diverse ichnocoenosis consisting of sauropod, ornithopod, theropod, and pterosaur trackways and isolated tracks. The sauropod trackways belong to the Brontopodus-type and were possibly left by medium-sized titanosaurs. One of the sauropod trackways turns around and makes an astonishingly narrow turn of more than 180° with very pronounced “off-tracking” of the manus with respect to the pes. Such unusual trackways are important for the reconstruction of sauropod locomotion. The theropod trackways were left by small and medium-sized animals with the imprint morphology being similar to that of the ichnogenera Grallator and Eubrontes. Large tridactyl tracks with blunt toes are tentatively identified as ornithopod tracks and may be described as Caririchnium-type tracks. Pterosaur tracks can be assigned to Pteraichnus. The association of pterosaur with small theropod tracks is rather unusual, and this tracksite further corroborates the frequent presence of large ornithopods in inland environmental settings.

Asianopodus-type footprints from the Hekou Group of Honggu District, Lanzhou City, Gansu, China and the “heel” of large theropod tracks

An increasing number of dinosaur tracksites have been reported from the Cretaceous Hekou Group deposits of the Lanzhou-Minhe Basin in the Gansu Province region. These include small sites such as the Huazhuang tracksite, from the Honggu District reported here, the Zhongpu tracksite with multiple track levels but few well-preserved tracks, other small tracksites currently under investigation, and the large and diverse Liujixia National Dinosaur Geopark site at Yanguoxia, where intensive study is ongoing. Collectively these sites reveal that ichnofaunas in the Hekou Group are widespread and diverse. The Huazhuang tracksite yields a small assemblage of moderately well-preserved theropod tracks assigned to Asianopodus. This is the first report of Asianopodus from the Hekou Group. Huazhuang Asianopodus belongs to the Eubrontes morphotype. The large theropod tracks from Lanzhou-Minhe Basin were left by large theropod trackmakers with the same general foot morphology. The specimens are described in detail and compared with other theropod track morphotypes from the Lower Cretaceous of China and elsewhere. In general, although the metatarsophalangeal pads of some Jurassic Eubrontes-type tracks are aligned with the axis of digit III, this feature appears most common in the Early Cretaceous theropod (Eubrontes-type) tracks.

Large theropod trackway from the Lower Jurassic Zhenzhuchong Formation of Weiyuan County, Sichuan Province, China: Review, new observations and special preservation

The well-preserved theropod track Weiyuanpus zigongensis, recently assigned to Eubrontes zigongensis, was not described in exhaustive detail at the time of its original discovery in 2007. Among the morphological details not described was an antero-medially directed hallux seen in five of the six tracks that make up the type trackway. Hallux traces are only rarely reported in large Lower Jurassic theropod tracks such as Eubrontes and Gigandipus, and their presence or absence may be the result of one or both of two factors: track depth and/or differences in hallux configuration in the trackmakers. Here we argue that E. zigongensis is one of the best preserved examples of a eubrontid track, which can be morphologically distinguished from other Eubrontes ichnospecies by the presence of well-defined hallux traces.

Estimating body weight and habitat type from extinct avian and avian-like theropod footprints

The relationship between body weight and footprint area of modern avians was derived and used to estimate the body weights of non-avian theropods taxa from the Triassic to Cretaceous and extinct avian taxa from the Cretaceous periods. Geometric information, such as the area and shape of fossil tracks of extinct avians and non-avian theropods, was used to estimate body weight and habitat type. The percentage prediction and standard error of estimates indicated that the body weight estimated from track area is comparable with body weight estimated from body fossils bones. Therefore, this approach is useful when the fossilized track record is richer than the fossilized skeletal record. The data sets for avians and reptiles were combined and used to derive a body weight–area relationship that may be applicable to a broader range of organisms, such as plantigrade quadrupeds and digitigrade bipeds. Additionally, scatter plots of the relationship between habitat type and footprint shape of modern avians were used to infer the habitat type of extinct avians. This finding suggests that the pes of animals, living in areas characterized by fluctuating water levels, and under conditions facilitating the preservation of footprints, were similar in form to those of extant semi-aquatic avians.

Large sauropod and theropod tracks from the Middle Jurassic Chuanjie Formation of Lufeng County, Yunnan Province and palaeobiogeography of the Middle Jurassic sauropod tracks from southwestern China

Tracks of large theropods and a single sauropod footprint are reported from red beds at Beikeshan locality in the Middle Jurassic Chuanjie Formation, of Lufeng County, near the large World Dinosaur Valley Park complex. The Chuanjie theropod tracks are assigned to the ichnogenus Eubrontes and the large sauropod track is given the provisional label Brontopodus. All occur as isolated tracks, i.e., trackways are not preserved. Saurischian dominated ichnofaunas are relatively common in the Jurassic of China. The producers of the Chuanjie tracks may have been similar to the basal tetanuran theropod Shidaisaurus and to mamenchisaurid sauropods, which were widely distributed throughout China, during the Jurassic, and are known from skeletal remains found in the same unit. Other potential sauropod trackmakers include titanosauriforms or as-yet-unknown basal eusauropods. The ichno- and skeletal records from the Jurassic of the Lufeng Basin are largely consistent, and both document the presence of middle-large sized theropods and sauropods.

Upper Cretaceous dinosaur track assemblages and a new theropod ichnotaxon from Anhui Province, eastern China

Several noteworthy Cretaceous tracksites are known in the Huizhou District (Huangshan City) in the Yangtzee valley of southern Anhui Province. These include some that have been known since the late 1970s but have not been studied in detail until now. The footprints described here occur in siliciclastic fluvial deposits in three distinct horizons. The Xiaohutian tracksite in the Upper Cretaceous Xiaoyan Formation is the most interesting, being situated at a historically famous location used as a Taoist and Buddhist shrine. The Xiaohutian tracksite yields an assemblage with three different morphotypes of non-avian theropod tracks including the new ichnotaxon Paracorpulentapus zhangsanfengi that can be attributed to a theropod with relatively short “fleshy” toes showing convergence with the footprints of small ornithopods. A further diagnostic feature is the trackway pattern with relatively short steps. Associated ichnofossils are invertebrate traces that can be assigned to eurybathic forms such as Palaeophycus and ?Planolites or ?Scoyenia. Thus far skeletal remains from the Xiaoyan Formation have proved the pachycephalosaur Wannanosaurus and indeterminate sauropods. The ichnoassemblages enlarge the known dinosaur fauna by small- to medium-sized theropods that are identified here as the trackmakers and that are otherwise rare in Upper Cretaceous deposits of eastern China. The Shangshangen locality is another significant tracksite which has yielded small bird tracks (cf. Koreanaornis) in association with small tracks of non-avian theropods.

Sauropod and Small Theropod Tracks from the Lower Jurassic Ziliujing Formation of Zigong City, Sichuan, China, with an Overview of Triassic–Jurassic Dinosaur Fossils and Footprints of the Sichuan Basin

A dinosaur footprint assemblage from the Lower Jurassic Ziliujing Formation of Zigong City, Sichuan, China, comprises about 300 tracks of small tridactyl theropods and large sauropods preserved as concave epireliefs (natural molds). The theropod footprints show similarities with both the ichnogenera Grallator and Jialingpus. Three different morphotypes are present, probably related to different substrate conditions and extramorphological variation. A peculiar preservational feature in a morphotype that reflects a gracile trackmaker with extremely slender digits, is the presence of a convex epirelief that occurs at the bottom of the concave digit impressions. It is possibly the result of sediment compaction underweight load when the pes penetrated the substrate, being a resistant residue during exhumation and weathering. The sauropod tracks belong to a trackway with eight imprints consisting of poorly preserved pes and manus tracks and a better preserved set, probably all undertracks. The narrow-gauge trackway pattern resembles the ichnogenus Parabrontopodus well known from the Jurassic but other features such as the minor heteropody are different. The assemblage enriches the dinosaur record from the famous Zigong locality and the evidence from the Lower Jurassic in this area that was restricted to a few skeletal remains and footprints. Furthermore it proves the presence of small theropods, whereas skeletons of the group, well- known from the Middle-Upper Jurassic of Zigong, are of medium to large size only. Remarkable is the dominance of saurischians in these assemblages, which is characteristic of Jurassic dinosaur communities whereas the Cretaceous record shows an increase of ornithopod groups. An overview of the dinosaur trace and body fossil record of the Sichuan Basin supports this view. The paleoenvironment can be designated as a low-latitude tropical freshwater lake as it is indicated by bivalve shells.

Dinosaur tracks from the Jurassic Shemshak Group in the Central Alborz Mountains (Northern Iran)

Abstract The Shemshak Group includes alternating layers of coal-bearing shale and siliciclastic sediments in the Baladeh area in the central Alborz Mountains of northern Iran. A diverse and abundant Jurassic dinosaur footprint assemblage is now recognized in the group, which is Toarcian to Bajocian in age in the northern Baladeh. This is the first report of a diverse dinosaur ichnoassemblage from Iran that includes the footprints of sauropods. These tracks can be assigned to three groups of trackmakers: theropods, ornithopods and sauropods. Those of theropods are typically tridactyl in shape, their trackways reflecting bipedal movement. Theropod footprints are very abundant in both northern and western Baladeh. The studied theropod tracks themselves are divided into three major dimensional groups. The medium sized footprints (footprint length, 11-15 cm) are abundant and have a stride length, digit and pace angles like the coelurosaurs footprints and trackway. Theropod footprints were identified as similar to Schizograllator otariensis, Talmontopus tersi and Wildeichnus isp. Ornithopod footprints are tridactyl with rounded and thick toes and belong to bipeds. Some didactyl imprints were also observed. Skin imprints were well preserved in these footprints. The ornithopod tracks resemble Jiayinosorupus johnsoni, as well as Velociraptorichnus sichuanensis for didactyl footprints. Sauropod footprints found in the western part of Baladeh are assigned here to Eosauropus isp., which are pentadactyl pes imprints of a quadruped. The assemblage from Iran resembles similar associations from eastern Asia.

The non-avian theropod track Jialingpus from the Cretaceous of the Ordos Basin, China, with a revision of the type material: Implications for ichnotaxonomy and trackmaker morphology

Deposits from the Ordos Basin of mid-western China are rich in body fossils and ichnofossils of Early Cretaceous vertebrates. Thousands of Early Cretaceous sauropod, theropod and bird tracks described since 1958 have been found at several localities in the basin. We report two new sites (Dijiaping and Bawangzhuang) in the Luohe Formation of the Ordos Basin, Shaanxi Province, which contain small theropod footprints that are here referred to the ichnogenus Jialingpus. The assignment is based on pad configurations including (1) the large metatarsophalangeal area positioned in line with the axis of digit III, (2) the subdivision of this part into a small pad behind digit II, which in some specimens is close to the general position of the hallux (digit I), and a large metatarsophalangeal pad behind digit IV, and (3) a distinct inter-pad space between metatarsophalangeal pads and proximal phalangeal pads of digits II and III. We re-describe the type material of the type ichnospecies Jialingpus yuechiensis from the Upper Jurassic Penglaizhen Formation of Sichuan Province, proposing a largely amended diagnosis for this ichnotaxon. The presence of a digit I trace in the holotype, indicating a relatively long hallux, and the large metatarsophalangeal area positioned in line with digit III distinguishes Jialingpus from the ichnogenus Grallator and similar tracks that all lack these features. The only difference between Jialingpus specimens from the Cretaceous of the Ordos Basin and those of the Jurassic Penglaizhen Formation is the larger digit divarication in the Cretaceous taxon. This is the fourth record of Jialingpus in China and the second in Cretaceous strata, with the first being those from the Huangyangquan locality in Xinjiang, China.

First report of the ichnogenus Magnoavipes from China: New discovery from the Lower Cretaceous inter-mountain basin of Shangzhou, Shaanxi Province, central China

Large, slender probable ornithomimid theropod tracks and robust theropod tracks occur in the Lower Cretaceous Fenjiashan Formation in Shaojian Village located southwest of Shangzhou City, Shaanxi Province, China. The large, slender tridactyl tracks of a biped are identified as Magnoavipes asiaticus ichnosp. nov. This is the first discovery of the ichnogenus Magnoavipes, a probable ornithomimid theropod track, in China. Co-occurrence of both Magnoavipes asiaticus and robust theropod tracks assigned to Megalosauripus ichnosp. indicates that two distinct trackmaking dinosaurs inhabited Early Cretaceous inter-montane basins. The Magnoavipes track-maker evidently expanded its habitat from inter-montane basins in the Early Cretaceous to fluvio-lacustrine and coastal plain environments in the Late Cretaceous.

Discriminating between Medium-Sized Tridactyl Trackmakers: Tracking Ornithopod Tracks in the Base of the Cretaceous (Berriasian, Spain)

BackgroundRecent work on the Jurassic-Cretaceous transition of the Iberian Range (Spain) has opened a new window onto the interpretation of the trackmakers of some medium-sized tridactyl tracks. The ichnotaxon Therangospodus oncalensis has been described in the Huérteles Formation (Berriasian) and is one of the classical tracks from the area assigned to medium-sized theropods.Methodology/Principal FindingsA review of the type locality of Therangospodus oncalensis (Fuentesalvo tracksite) and other tracksites from the Huérteles Formation (Berriasian) has yielded new information on the morphology, gait and trackmaker identity of the aforementioned ichnospecies. The new data suggest that the trackmaker is an ornithopod rather than a theropod on the basis of the length/width ratio, the anterior triangle length-width ratio, the short steps, the round to quadrangular heel pad impression and the probable manus impressions. Conclusions/Significance T. oncalensis shows similarities with various tracks from the Berriasian of Europe assigned to Iguanodontipus. The ichnotaxonomical status of this ichnospecies is here considered as Iguanodontipus? oncalensis due to the current state of knowledge of the ichnotaxonomy of medium-sized ornithopod tracks. This reassessment of I? oncalensis also has two significant implications for the palaeoecology of the faunas during the deposition of the Huérteles Formation: 1- the high number and percentage of theropod tracks would be lower than previous papers have suggested. 2- the gregarious behaviour described in the type locality (Fuentesalvo) would be among ornithopods instead of theropods.